Fig. 13 shows the arrangement of the machinery for hoisting and pumping, which was identical at the several shafts, except that the hurdy-gurdies varied from 16½ feet in diameter at the upper shaft to 21 feet at the lowest shaft. The water-wheel moved only in one direction; the pinion on the wheel-shaft drove the spur-wheel, to which the pitman of the pump-bob was attached. On the spur-wheel shaft was a friction-gear, driving the hoisting-reel; this reel was mounted on sliding blocks, so that hoisting was done by putting it in gear, the empty load being dropped by a friction-band. Changing the size of the water-wheel as the pressure increased permitted the use of the same pattern of machinery at the different shafts. The water was brought to the wheel by a discharge-pipe, some nine feet long, having a vertical movement by ball-and-socket joint, so that at pleasure, by dropping the pipe, the machinery could be run at various speeds, or entirely stopped. At the end of this discharge-pipe was a cast tapered nozzle, about 3½ inches in diameter, in which was inserted a ring of saw-plate steel having the desired diameter, and which was held in place by an annular screw-cap. By changing the ring, which only required a few moments' time, any desired amount of water, up to 3 or 4 cubic feet a second, could be discharged against the wheel. The stop-gate was left wide open while the machinery was running. The pumping was done by eighteen pumps, of Cornish pattern; the largest amount of water pumped from any one shaft was something over 30 cubic feet a minute; the power at hand, however, was ample to pump more than twice that quantity. It was rather curious at, this shaft to see more water coming from the pumps than was used on the wheel. The two diamond drills were driven by a small hurdy-gurdy set on the rear of the drill carriage. This, but at another tunnel, was afterward modified by placing a separate hurdy-gurdy on a sleeve on each drill-rod; the advance movement of the drill being given by hydrostatic pressure on an annular piston, thus doing away with all gearing. These eight sets of machinery were run for nearly 2½ years' time; the only break being that of a spur-wheel, doubtless caused by the careless dropping of a steel bar between it and its pinion. Aside from this accident, practically not a dollar was spent for repairs, and the machinery, including the pipe, was in about as good order when the tunnel was finished as when it was first erected. One man, on a twelve hour shift, operated the machinery at each shaft, besides dumping the cars; two men kept the 18 pumps on the line in order, the principal work being in keeping the suction-pipes for the down-grade headings tight; thus a force of 18 men was only required for the eight shafts. The cost of the pipe, gates, etc., when put in place, was $14,631, and of the machinery about $60,000.
Infrastructure Journal
Scientific American Supplement, No. 455, September 20, 1884 — Part 46
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